Optical counters have been utilized in various applications to count objects. Typically, these counters include a feed system to reduce the collection of objects to a single-file orderly line, an optical sensor apparatus and a counting system. Various mechanical systems for producing a single-file flow include rotational and linear vibrators, rotating discs, air jets, gravity feeds, moving belts, etc. In such optical counters, the counting apparatus that performs the actual count of a single-file flow is simple in concept. A light source is placed opposite a single optical sensor and the object stream is directed between the sensor and the light source. The shadows created by the objects yield alternating light and dark patterns on the sensor. The sensor produces an electrical signal representative of these patterns and transmits the electrical signal to an electrical counting apparatus.
Accurate counts are possible provided the flow of objects is in a discrete series of single objects. Any failure of the mechanical feed system that results in flow that is not discrete will cause an inaccurate count. Inaccurate counts are due to the operation of the sensor which changes state in response to the presence or absence of light without respect to whether a light blockage is caused by one or more objects. Thus, if two or more objects cross the sensor simultaneously or if two or more objects are in physical contact, the count will be erroneous because a one to one correspondence between discrete objects and sensor state changes did not exist. This condition in the object flow stream is referred to as "bunching".
In this type of counter, stringent demands are placed on the feed system because of the unforgiving nature of the sensors. These systems are typically complex and require parts changes and adjustments for each different size and shape object being counted. Thus, the set up requires a skilled operator. An object counter of this kind achieves accurate count at the sacrifice of size, complexity and cost.
Heretofore known electronic systems are not highly accurate, particularly when small objects such as pharmaceutical capsules, tablets, etc. are to be counted. Such systems have lacked the sophisticated sensing and counting electronics and "intelligent" software to drive the electronics.
The foregoing problems of prior art optical counters manifest the need for improvement. Specifically, there is a need for an optical counting system which reduces the requirement for a high performance feed system and is capable of identifying and counting objects which are bunched together with a high degree of accuracy. Such a counting system would be able to "intelligently" observe the object stream to recognize and account for deviations from the ideal discrete object flow.